Background of the Invention
The present invention relates to a flying spherical body measuring apparatus for measuring the flight velocity, flight direction and rotational amount around various axes of rotation such as during back spin, side spin and the like of a rotating, flying spherical body such as a golf ball when struck by a club. In addition, the present invention relates further to a flying spherical body measuring apparatus for measuring the angle of elevation, horizontal angle, and flight velocity of a flying spherical body possessing a high flight velocity.
Measuring devices, such as those described in the following, for measuring the initial angle, flight velocity and like of a golf ball struck by a club are known.
(1) Japanese Patent Application, First Publication Laid Open No. 48-40514 discloses an apparatus in which a semicircular super reflective strip is placed on a ball, after which light is irradiated at the flying ball from a lighting system. The light reflected by the aforementioned strip is then detected by a plurality of sensors. Using the results detected by these sensors, this apparatus then calculates the range, offset distance to the left or right side caused by pull or slice spins, difference between the ball height and the ideal height, and the like, which would result when the player actually played on a golf course.
(2) Japanese Patent Application, First Publication No. 55-146046 discloses an apparatus in which at least two reflective marks are affixed to the circumference of the golf ball spanning the back spin. These reflective marks are affixed at a predetermined angle .theta..degree. with regards to the center of the ball. After the ball is struck, when a reflective mark faces the light-projecting and light-receiving faces, the light from the light-projecting face is reflected by the reflective mark to the light-receiving face, and then transformed into an electric signal by the light-receiving device. In the case when two reflective marks are affixed to the ball, two electric signals are obtained per one revolution of the ball, and the electric signal thereby increases. The time interval is then measured, and the spin amount is calculated.
In addition, Japanese Patent Application, First Publication Laid Open No. 2-272310 discloses a turning angle measuring apparatus for measuring the rotating angle of a rotating body to which a detection mark has been affixed. The rotating angle is measured by means of photoelectrically or magnetically reading the aforementioned detection mark.
(3) An apparatus is also known which is equipped with a magnetic sensor for detecting the club head impact parameter just before its impact. At the time of the impact, the head velocity, face angle, blow direction, hitting area and the like of the club head are calculated based on the AC waveform obtained from the magnetic sensor. In addition, in order to detect the motion of the ball after impact, two types of ball detection portions are sequentially arranged along the flight direction of the ball. Each ball detection portion is constructed in a manner such that the flight line of the ball lies in between an infrared diode and a plurality of phototransistors which are arranged facing each other. In this type of construction, following impact, when the output light of the infrared diode is interrupted by the ball, a ball detection signal is obtained from the phototransistor which was supposed to receive this output light. In this manner, the initial flight direction (angle of horizontal deviation), angle of elevation, initial velocity and the like are calculated based on the detection signal obtained from each respective phototransistor of each ball detection portion. The detection signal generated by the phototransistor of each ball detection portion incorporates not only a component corresponding to the infrared diode inside the same ball detection portion, but also contains a component corresponding to the infrared diode inside the other ball detection portion. Consequently, in order to detect the position of the ball, it is necessary to divide these two components within the detection signal. Consequently, each infrared diode is driven by means of a two-phase pulse signal in which the phases are set off from each other by 180.degree.. In addition, each of the two components incorporated into the detection signal of the phototransistor are sampled by means of two types of sampling pulses simultaneously generated with each pulse signal. By means of this ball detection signal, the position of the ball is detected, and the horizontal angle of the ball flight (angle of horizontal deviation), angle of elevation, initial velocity and the like are calculated from the results of this detection (see Mitsubishi Electric Giho, vol. 58: No 2, 1984).
(4) Japanese Patent Application, Second Publication No. 58-44387 discloses an apparatus in which two types of ball detection portions are sequentially arranged along the flight direction of the ball. Each ball detection portion is constructed in a manner such that the flight line of the ball lies in between a light source and a plurality of phototransistors which are arranged facing each other. Each light source utilizes a sealed box with a slit in the front face which houses an illuminating device and a means for converging the output light of this illuminating device. The output light of each light source is also designed to be received by the respective corresponding phototransistors. By means of this structure, the elapsed time and distance traveled for PG,4 the ball as it passes through each ball detection portion is calculated based on the detection signal obtained from each phototransistor, and based on these calculations, the velocity of both the club and ball am measured.
Additionally, apparatuses for measuring the flight angle and velocity of a ball by optical detection of the ball are disclosed in Japanese Patent Application, First Publication Laid Open No. 49-111729, Japanese Patent Application, First Publication Laid Open No. 56-43505 and Japanese Patent Application, First Publication Laid Open No. 61-204514.
However, in the above-mentioned measuring apparatuses (1) and (2) above, only special balls provided with super reflective strips, detection marks and the like can be used, and thus there exist drawbacks in that it is necessary to confirm and align these marks for every stroke.
In addition, another problem arises in that all of the aforementioned measuring apparatuses have complex constructions. In particular, in the case of apparatus (3), disadvantages exist such as the requirement of two types of ball position detection means, the heavy influence of the construction accuracy on the measuring accuracy, employment of a large number of components, as well as, high costs. In addition, no consideration was given in regard to the shape of the flying body, i.e. that a ball is a spherical body, and thus the calculation accuracy is low. Furthermore, in apparatus (4), only the velocity of the club and ball can be measured, and in order to improve the measuring accuracy, it is necessary for the initial position of the ball and the sensor to be placed far apart resulting in an increase in size of the apparatus.